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authorOleg Nesterov <oleg@redhat.com>2014-04-21 20:39:56 +0200
committerOleg Nesterov <oleg@redhat.com>2014-04-30 19:10:37 +0200
commit220ef8dc9a7a63fe202aacd3fc61e5104f6dd98c (patch)
tree1176022547d4fd10b216612e0b73440570520015 /arch/x86/kernel/uprobes.c
parent6ded5f3848bfd3227ee208aa38f8bf8d7209d4e3 (diff)
downloadop-kernel-dev-220ef8dc9a7a63fe202aacd3fc61e5104f6dd98c.zip
op-kernel-dev-220ef8dc9a7a63fe202aacd3fc61e5104f6dd98c.tar.gz
uprobes/x86: Move UPROBE_FIX_SETF logic from arch_uprobe_post_xol() to default_post_xol_op()
UPROBE_FIX_SETF is only needed to handle "popf" correctly but it is processed by the generic arch_uprobe_post_xol() code. This doesn't allows us to make ->fixups private for default_xol_ops. 1 Change default_post_xol_op(UPROBE_FIX_SETF) to set ->saved_tf = T. "popf" always reads the flags from stack, it doesn't matter if TF was set or not before single-step. Ignoring the naming, this is even more logical, "saved_tf" means "owned by application" and we do not own this flag after "popf". 2. Change arch_uprobe_post_xol() to save ->saved_tf into the local "bool send_sigtrap" before ->post_xol(). 3. Change arch_uprobe_post_xol() to ignore UPROBE_FIX_SETF and just check ->saved_tf after ->post_xol(). With this patch ->fixups and ->rip_rela_target_address are only used by default_xol_ops hooks, we are ready to remove them from the common part of arch_uprobe. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Diffstat (limited to 'arch/x86/kernel/uprobes.c')
-rw-r--r--arch/x86/kernel/uprobes.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 2efb93f..b2bca29 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -441,6 +441,9 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs
return -ERESTART;
}
}
+ /* popf; tell the caller to not touch TF */
+ if (auprobe->fixups & UPROBE_FIX_SETF)
+ utask->autask.saved_tf = true;
return 0;
}
@@ -757,15 +760,15 @@ bool arch_uprobe_xol_was_trapped(struct task_struct *t)
int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
+ bool send_sigtrap = utask->autask.saved_tf;
+ int err = 0;
WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
current->thread.trap_nr = utask->autask.saved_trap_nr;
if (auprobe->ops->post_xol) {
- int err = auprobe->ops->post_xol(auprobe, regs);
+ err = auprobe->ops->post_xol(auprobe, regs);
if (err) {
- if (!utask->autask.saved_tf)
- regs->flags &= ~X86_EFLAGS_TF;
/*
* Restore ->ip for restart or post mortem analysis.
* ->post_xol() must not return -ERESTART unless this
@@ -773,8 +776,8 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
*/
regs->ip = utask->vaddr;
if (err == -ERESTART)
- return 0;
- return err;
+ err = 0;
+ send_sigtrap = false;
}
}
/*
@@ -782,12 +785,13 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
* so we can get an extra SIGTRAP if we do not clear TF. We need
* to examine the opcode to make it right.
*/
- if (utask->autask.saved_tf)
+ if (send_sigtrap)
send_sig(SIGTRAP, current, 0);
- else if (!(auprobe->fixups & UPROBE_FIX_SETF))
+
+ if (!utask->autask.saved_tf)
regs->flags &= ~X86_EFLAGS_TF;
- return 0;
+ return err;
}
/* callback routine for handling exceptions. */
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